This study will examine the resistance of corneal epithelial cells to infectious agents. The animal models to be studied will be guinea pig inclusion conjunctivitis in guinea pigs and herpes simplex virus in rabbits. In immune and non-immune animals the infectivity of these two agents for the corneal epithelium will be determined by recovery of agent from standard sized specimens of corneal epithelium at the end of the first growth cycle of the agent. Electron microscope studies will be done to indicate what cell layer is invaded, what the reaction of the cell is to infection and what the cytochemical response is within the cell. Studies on clinical specimens will include material obtained at corneal transplant surgery and from conjunctival scrapings. These studies will be particularly concerned with herpes simplex virus, adenovirus, conjunctivitis and trachoma-inclusion conjunctivitis infections.